Compression spring actuating mechanism for toggle-operated momentary electrical switches



W. T. SORENSON MOMENTARY ELECTRICAL SWITCHES Filed Oct. l0, 1962 NN bw N\ s@ AT ORNEY Jan. l2, 1965 coMPREssIoN SPRING ACTUATING MECHANISM FOR ToGGLE-OPERATED United States Patent O 3,165,603 COMPRESSION SPRING ACTU ATING MECHANISM FOR TOGGLE-OPERATED MOMENTARY ELEC- TRICAL SWITCHES Wesley T. Sorenson, West Hartford, Conn., assignor t lCarling Electric, Inc., West Hartford, Conn., a corporation of Connecticut Filed Oct. 10, 1962, Ser. No. 229,531 Claims. (Cl. ZOO- 67) This invention relates generally to spring actuated mechanisms, and more particularly to an improved toggle spring mechanism suitable for momentary electric switches and the like.

In momentary switches, where a spring holds the toggle element in a normally open circuit position, the usual practice in the past has been to anchor both ends of the return spring. Where the mechanism is large enough, the problem of anchoring the return spring at both ends is not very serious since there is ample room to provide suitable clips, lugs, or rivets, for that purpose. When it is necessary, however, to produce a small momentary switch where space is extremely limited, the problem of anchoring a return spring at both ends becomes troublesome and also involves considerable'assembly difficulties.

In order to overcome these difficulties, the present invention offers the solution of holding captive one end portion only of the spring within the toggle element itself, while the other free end of the spring is movable along the wall of the bushing that contains the toggle mechanism when the latter is actuated. In this manner an extremely simple and inexpensive means is achieved for producing a reliable and long-lasting toggle-return spring mechanism.

In `order to ensure that the return spring performs its function properly, the accommodating recess in the toggle is suiiiciently deep to hold captive a suiiicient end portion of the return spring, which, in some embodiments, may be up to half or more of the length of the spring, so that the spring would naturally be compressed on a substantially straight axis when the toggle is moved pivotally within the bushing while the free end of the spring moves slidably along the inner wall of the bushing.

Another factor for ensuring the straight line compression of the return spring is the alignment of the toggle spring aperture at an acute angle from the perpendicular to the toggle axis, so that the spring will be prevented from compressing on a bent axis and fatiguing when the toggle is moved pivotally.

A further factor that is contributory to the straight' line compression of the spring is the selection of the proper tension and stiffness characteristics of the return spring itself as related to the dimensions of the other components of the toggle assembly.

Still other objects and advantages of the invention will be apparent from the specification.

The features of novelty which are believed to be characteristic of the invention are set forth herein and will best be understood, both as to their fundamental principles and as to their particular embodiments, by reference to the specification and accompanying drawings, in which:

FIGURE l is a top View of the momentary switch of the present invention;

FIG. 2 is a greatly enlarged partial section view taken on line 2-2 of FIG. 1, showing the momentary switch in the open circuit condition with the toggle handle at rest;

FIG. 3 is a view similar to FIG. 2, showing the switch in the momentary closed circuit condition; and

FIG. 4 is a partial section view taken on line 4 4 ice of FIG. 3, with the toggle handle and some of the switch elements in a vertical position intermediate the open and closed circuit conditions.

Referring now to the drawing in detail, the momentary switch of the present invention comprises a case, generally designated 11, molded or otherwise formed of a suitable insulating material such as Bakelite, nylon, or the like, said case having a bottom wall 12, a pair of opposed side walls 13 and 14, and a pair of end walls 1d and 17, said walls being formed integrally with each other to enclose an interior chamber 1S. Chamber 18 has a concave floor 19, which is divided longitudinally by a short partition 21 integrally formed therein, the concave top of said partition being raised somewhat above floor 19.

Positioned in a pair of vertical spaced apart slots 22 in wall 17 are electrically conductive vertical contact elements 23 and 24- whose forwardly extending integral legs 26 and 27, respectively, lie in a pair of accommodating recesses 28 in bottom wall 12. The inner edges 31 of elements 23 and 24, and the upper edges 32 of legs 26 and 27, slope inwardly into chamber 18 and join at an angle therein.

integrally formed `at the upper ends of contact elements 23 and 24 are horizontal arms 33 which extend outwardly through apertures 34 in wall 17 and terminate on the exterior of case 11 in a pair of terminal lugs 36, which are threadably engaged by screws 37 for connecting said contact elements to an electrical circuit controlled by the switch.

Positioned on top of case 11 is a roof plate 41 made of a suitable insulating material, said roof plate being clamped in position by means of a sheet metal cover plate 4.12 secured to case 11 by studs 43. Both roof plate 41 and cover plate 42 have aligned apertures which permit communication with the interior chamber 18 of case 11. Surrounding its aperture, cover plate 42 has an upwardly extending annular iiange 44 to which is connected by suitable means the lower end of a bushing 46 whose bore 47 is aligned with the apertures of roof plate 41 and of said cover plate. The upper portion of bushing 46 accommodates pivot pin t8 which extends diametrically through the reduced diameter bore 49, of said bushing. Pivotally mounted on pin 48 is a toggle element 51 having an integral upwardly extending tog-V gle handle 52, which is manipulated for operating the momentary switch. The bottom of toggle 51 has an integral extension 53 movable laterally within bore 47 of bushing 46.

The lower end of extension 53 terminates in a downwardly extending nib 54 which is slidably engaged by a ring 56 secured to the upper end of a coiled spring element 57. The other end of spring element 57 is engaged in an annular recess of carriage 58 which has an integral downwardly extending stub 59, the lower edge of which has a concave recess 61 rotatably accommodating electrically conductive shaft 62, whose respective ends are integrally formed into roller contacts 63 and 64. Roller contacts 63 and 64 are adapted to roll back and forth on lioor 19 on either side of partition 21 within chamber 18 of case 11. In the open circuit condition of the switch, as shown in FIG. 2, roller contacts 63 and 64 are spaced apart from edges 31 and 32 of contact elements 24 and legs 27, respectively. In the closed circuit condition of the switch as shown in FIG. 3, roller contacts 63 and 64 are abutted against edges 31 and 32 of both contact elements 24 and of both legs 27, respectively, whereby the electrical `circuit between terminals 36 is closed through electrically conductive shaft 62.

Extension 53 of toggle element 51 has a lateral recess 66 which coaxially holds captive a portion of a coiled return spring 67, the other free end of which abuts the inner wall of bore 47 of bushing 46. Normally, as shown in FG. 2, return spring 67 is operative upon toggle 51 to urge toggle handle 52 to the Vleft while nib 54 is urged to the right along with ring 56. When the latter moves to the right, spring 57 causes carriage 58 to move to the left along with roller contacts 63 and 64. Thus, under the action of return spring 67, an open circuit condition obtains in the switch.

When toggle handle 52 is momentarily moved to the right, against the action of return spring 67, as shown in FIG. 3, the movements of all of the parts are reversed, to cause roller contacts 63 and 66 to move to the right whereby the electrical circuit is closed between terminals 36.

When the switch is in the open circuit condition as shown in PEG. 2, partially or slightly compressed return spring 67 maintains its free end abutted against the inner wall of bore 47 intermediate the upper and lower limits thereof, and maintains its other end portion captive in recess 66, while toggle element 53 is urged to the right.

The length of the diameter `of bore 47 of bushing 46 is selected so that spring 67 maintains itself in the position shown without danger of fallingr out of recess 66.

When the switch is momentarily actuated as shown in FIG. 3, and spring 67 is compressed into recess 66, the free end of the latter moves slidably and upwardly along the inner wall of bore 47 until the edge thereof is limited in its motion by shoulder 69 formed between bores t7 and 49 of bushing 46. By this action, roller contacts 63 and 64 are urged fby the action of spring 57 to the right to close the circuit between terminals 36.

In one embodiment, as illustrated, the axis and bore of recess 66, which holds a portion of spring 67 captive, are a'rrayed at an acute angle from the perpendicular to the common longitudinal axis of toggle handle 52 and nib d. The reason for setting recess 66 at such an angle is to prevent the central portion of return spring 67 from unduly iiexing prior to its being compressed into said recess as shown in FIG. 3. The axis of recess 66 is arranged at a suitable angle so that during the movement of toggle element 53 to the left, return spring 67 will be compressed on asubstantially straight axis while its outer free end is moving upwardly. A further factor in ensuring the compression of return spring 67 on a substantially straight axis into recess 66 is the provision of adequate depth in said recess for the normal accommodation lof a sufficient captive portion of said spring when said toggle is in the open circuit position as shown in FIG. 2.

lf the axis of recess 66 is not properly arrayed relative to the toggle elements as well as to the wall of bore 47, then return spring 67 would be compressed on a bent axis and after several iiexures thereof the spring would fatigue, ultimately break or twist out of recess 66, escape captivity and `fall into chamber 18, which would constitute failure of the device.

When toggle 'handle 52 is released, return spring urges toggle pivotally to its original open circuit position as shown in FIG. 2. By this action, return spring expands and its free end slides downwardly along the wall of bore t7 of bushing 46 to its original position, while roller contacts 63 and 64 are returned under the action of spring 57 to the left to open the circuit between terminals 36.

In some embodiments, the axis of cylindrical recess 66 is arrayed at approximately 8 upwardly from the perpendicular to the axis of the toggle elements. The optimum range of acute angles from said perpendicular as well as the depth of recess 66 would be established empirically depending upon the sizes of the Various components of the switch, upon the diameter of bore 47 of bushing 46, and upon the tension and stiffness characteristics yof return spring 67 itself.

It is claimed:

1. A momentary switch comprising a switch case, a bushing on said case, a toggle element pivotally mounted within said bushing, said toggle element being movable between an open circuit position and a closed circuit position, a lateral recess in said toggle element, and a spring, one end portion of said spring being held captive in said recess, the'other free end of said spring abutting andVv slidable along the interior wall of said bushing, said l spring normally urging said toggle element into the open circuit position, the movement of said toggle element to the closed circuit position causing the compression of said spring into said recess while the `free end thereof moves slidably `along said interior wall.

2. A switch according to claim 1, and further comprising an abutment in the interior of said bushing, said abutment being located to limit the movement of the free end of said spring when the toggle is in the closed circuit position.

3. A momentary switch comprising a case, a toggle element pivotally mounted iin said case, said toggle element being movable between an open circuit position and a closed circuit position, a lateral recess in said toggle element, and a spring, at least half of the length of said spring being held captive coaxially in said recess, the other free end of `said spring abutting and being slidable along the interior wall of said case, said spring normally urging the said toggle element into the open circuit position, the movement of said toggle element to the closed circuit position causing the compression of said spring into said recess while the free end of ysaid spring moves slidably along said interior wall.

4. A switch according to claim 3 wherein said spring is compressed into said recess on a substantially straight axis while said toggle moves from the open circuit position to the closed circuit position.

5. A switch according to claim 3 wherein the angle of the axis of said recess relative to the axis of said toggle element is selected and the length of said spring relative to the dimensions of said toggle element and said case is selected to provide for the compression of said spring on a substantially straight axis into said recess when said toggle element is moved from the open circuit position to the closed circuit position.

References Cited by the Examiner UNITED STATES PATENTS 2,863,965 12/58 Cardin et al. 200-113 FOREIGN PATENTS 698,821 10/53 Great Britain.

BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner. 

3. A MOMENTARY SWITCH COMPRISING A CASE, A TOGGLE ELEMENT PIVOTALLY MOUNTED IN SAID CASE, SAID TOGGLE ELEMENT BEING MOVABLE BETWEEN AN OPEN CIRCUIT POSITION AND A CLOSED CIRCUIT POSITION, A LATERAL RECESS IN SAID TOGGLE ELEMENT, AND A SPRING, AT LEAST HALF OF THE LENGTH OF SAID SPRING BEING HELD CAPTIVE COAXIALLY IN THE RECESS, THE OTHER FREE END OF SAID SPRING ABUTTING AND BEING SLIDABLE ALONG THE INTERIOR WALL OF SAID CASE, SAID SPRING NORMALLY URGING THE SAID TOGGLE ELEMENT INTO SAID OPEN CIRCUIT POSITION, THE MOVEMENT OF SAID TOGGLE ELEMENT TO THE CLOSED CIRCUIT POSITION CAUSING THE COMPRESSION OF SAID SPRING INTO SAID RECESS WHILE THE FREE END OF SAID SPRING MOVES SLIDABLY ALONG SAID INTERIOR WALL. 